Audio Engine Subsystem

This project is a low-level audio engine module built using XAudio2 and integrated into a custom game engine as part of an engine programming course. The project required us to choose a feature our engine didn’t have (it only had basic graphics) and build an engine subsystem to handle that feature. I chose audio, because I love working with audio.

The goal was to:

  • Implement basic audio playback from scratch

  • Design a platform-independent interface

  • Ensure the system was usable by other programmers in a shared engine environment

Features and Function

Considerations

Key Takeaways

Audio Playback Pipeline

The system supports basic sound playback through an Audio Source abstraction.

This Audio Source API looked like this:

Which allowed other programmers to:

  • load a sound from a path

  • trigger playback with minimal setup

  • integrate this system quickly into their engine and gameplay systems

Data Flow:

  • Audio data is loaded during initialization

  • WAV file data is parsed (chunk-based loading)

  • Audio buffers are filled and submitted to an XAudio2 voice

  • Playback is controlled via the Audio Source interface

static cResult Load(const char* i_path, AudioSource*& o_source);

cResult Initialize(const char* strFilename);
cResult CleanUp();

cResult PlayOnce();
cResult PlayLooped();
cResult Pause();
cResult Reset();

Platform-Independent Design

A key requirement of the project was hiding platform-specific implementation behind platform-independent interfaces. In this case, the “platform” was XAudio2. So basically, users didn’t need to know anything about XAudio2 to use this subsystem.

This mattered because, in our final project, the various subsystems we wrote would be shared between classmates and then used to make a game. So making the interface easy to use was a priority.

And in fact, I did get a lot of positive feedback about that. My peers said it was easy to use and integrated quickly into their games. Nearly everyone in the class used my engine system because it was the only one for audio.

Constraints and Scope

As much as I would’ve liked to, this system did not contain any of the following features:

  • Spatial audio

  • Attenuation

  • Listener-based processing

This was partially due to time constraints, but more significantly was because it would make the interface more complex. After speaking to a few classmates, I realized that there was no demand for such features, and adding them would just add more parameters and objects into the system. So they were cut.

Understanding the audio stack

This was my first foray into low-level audio. I learned a lot about:

  • How audio data is structured

  • How buffered are submitted for playback

  • How low-level APIs expose control over sound.

API Design for other Engineers

This was also the first time I had to write an API other engineers would use. Designing for other programmers led me to:

  • Keep the interface minimal

  • Prioritize clarity over feature count

  • Think about how systems are consumed, not just built

Foundation for Future Audio Work

While this system is simple, it established a foundation for:

  • Understanding modern audio middleware like Wwise (which I worked with later on)

  • Thinking about how higher-level tools map onto low-level behavior

  • Exploring more advanced systems (DSP, spatialization, etc.)

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